In a conventional loudspeaker having an illumination function, for example, a light source is disposed in front of a diaphragm so that light from the light source is reflected by the diaphragm. Alternatively, a light source is disposed behind the diaphragm so that the light from the light source passes through the diaphragm.
Note here that as prior art literatures relating to the invention of the present application, PTL 1 is known, for example.